1. Field of the Invention
The present invention relates to a printing system that includes a printing apparatus, a post-processing apparatus, and a control method thereof.
2. Description of the Related Art
In recent years, a print-on-demand (POD) printing system has been proposed that includes an electrophotographic or inkjet printing apparatus and a post-processing apparatus, and that performs a bookbinding process on sheets that have been printed by the printing apparatus (U.S. Publication No. 2004-0190057). With this sort of POD printing system, printing plate making processes and other complicated tasks essential for a conventional bookbinding process can be significantly reduced.
This sort of printing system has an in-line mode where a printing process by a printing apparatus and a post-process on sheets that have been printed in the printing process are performed successively and an off-line mode in which only a post-process is performed without the involvement of a printing process by a printing apparatus. A system has also been proposed in which, in this off-line mode, where a second user interface provided on the post-processing apparatus, and not a first user interface provided on the printing apparatus, is used to perform a post-process on sheets set in a paper feed unit (Japanese Patent Laid-Open No. 2004-145200).
However, the above-described POD printing system still has many problems in terms of practicability. For example, it is desirable that the first user interface of the printing apparatus can instruct a post-process both in the in-line mode and the off-line mode. Furthermore, it is necessary that the post-process instructed by the first user interface is properly controlled according to whether the process is a process in the in-line mode or a process in the off-line mode.
Meanwhile, it is desirable that the second user interface of the post-processing apparatus can instruct at least one of post-processes in the off-line mode that can be instructed by the first user interface. Furthermore, it is necessary that control is properly performed such that a post-process in the off-line mode instructed by the first user interface and that by the second user interface do not conflict with each other.
Moreover, it is desirable that, even when the printing apparatus cannot be used due to power constraint or any other troubles, the second user interface of the post-processing apparatus can be used to perform a post-process by instructing that post-processing apparatus to perform the post-process.